This nonprovisional application claims priority under 35 U.S.C. xc2xa7119(a) on Patent Application No. 2001-284061 filed in Japan on Sep. 18, 2001, the entirety of which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a coupler mounting structure for vessels, and more particularly to a mounting structure of a driven side coupler coupled with a front end of an impeller driving shaft of the vessel.
2. Description of the Background Art
In the background art, coupler mounting structures for vessels as shown in FIG. 8 (Japanese Patent Laid-Open No. 112679/1995) and in FIG. 9 (Japanese Utility Model Registration No. 2542418) are known. The entirety of each of the aforementioned references are hereby incorporated by reference.
In the structure shown in FIG. 8, the midsection of the impeller driving shaft 1 in the vessel is supported on the vessel body via a bearing member 2, and the driven side coupler 3 to be coupled with a coupler (not shown) on the side of the output shaft of the engine is mounted on the front end 1a of the shaft 1. The shaft 1 is formed with a spline 1b at the front end 1a, and a cylindrical torque transmission member 4 is fixed in a boss 3a on the driven side coupler 3 by welding. The spline 4a formed on the inner peripheral surface of the torque transmission member 4 engages with the spline 1b of the aforementioned shaft 1. The shaft 1 is supported by the bearing member 2 via a sleeve 5, and the front end 5a of the sleeve 5 and the rear end 4b of the torque transmission member 4 are fixed by welding. Since the shaft 1 and the torque transmission member 4 fixed to the driven side coupler 3 are spline-connected with this type of structure, the shaft 1 can be pulled out rearward of the vessel body (toward the impeller which is not shown in the direction shown by the arrow R).
In the structure shown in FIG. 9, the midsection of the impeller driving shaft 6 in the vessel is supported on the vessel body 8 via a bearing member 7, and the driven side coupler 9 to be coupled with the coupler (not shown) on the side of the output shaft of the engine is mounted on the front end 6a of the shaft 6. The shaft 6 is formed with a thread at the front end 6a, e.g., at the mounting portion for the driven side coupler 9, and the boss 9a of the driven side coupler 9 is also formed with a thread on the inner surface thereof. The shaft 6 is formed with a flange portion 6b integrally at the rear portion of the mounting portion 6a for the driven side coupler 9. Therefore, with this type of structure, the driven side coupler 9 can be fixedly mounted on the shaft 6 by screwing the driven side coupler 9 on the front end 6a of the shaft 6 until it abuts against the flange portion 6b. 
In the structure of the background art shown in FIG. 8, since the shaft 1 and the torque transmission member 4 fixed to the driven side coupler 3 are engaged only by a spline, the shaft 1 and the torque transmission member 4 fixed to the driven side coupler 3 are capable of relative movement in the thrust direction at this spline-engaged portion. Since the reaction force from the impeller (not shown) is exerted on the shaft 1 discontinuously and indefinitely in strength, the shaft 1 and the torque transmission member 4 fixed to the driven side coupler 3 vibrates relatively at the spline-engaged portion in the thrust direction by the action of the reaction force, and thus both spline portions are susceptible to wear. Therefore, in the structure of the background art shown in FIG. 8, there is a problem in that durability at the connecting portion between the shaft 1 and the driven side coupler 3 is not necessarily good.
In the structure shown in FIG. 9, since the driven side coupler 9 can be fixedly mounted to the shaft 6, durability at the mounting portion is improved. However, since the shaft 6 is formed with the flange portion 6b integrally therewith, the shaft 6 cannot be pulled out rearwardly of the vessel body (toward the impeller in the direction of the arrow R). Therefore, when replacing the shaft 6 for maintenance, it is necessary to remove the impeller (not shown) at the rear end first, and then pull the shaft 6 out toward the front (in the direction shown by the arrow F). However, since there is a drive side coupler and an engine forwardly thereof, the engine must be removed before pulling the shaft 6 out. In other words, in the structure shown in FIG. 9, there is a problem in that it is troublesome to perform maintenance on the shaft 6.
The present invention overcomes the shortcomings associated with the background art and achieves other advantages not realized by the background art.
An object of the present invention is to provide a coupler mounting structure for vessels in which the above-described problems identified by the inventors are solved.
An object of the present invention is to provide a coupler mounting structure with improved shaft durability at the mounting portion for the driven side coupler.
An object of the present invention is to provide for easy and reliable maintenance of a coupler mounting structure.
One or more of these and other objects are accomplished by a coupler mounting structure for vessels in which an impeller driving shaft in the vessel is supported on a midsection of a vessel body by a bearing member and driven by an output shaft of an engine, the coupler mounting structure comprising a driven side coupler being mounted on a front end of the impeller driving shaft; a drive side coupler being operatively engaged with the driven side coupler for transmitting a driving force from the engine output shaft; and a collar having a diameter larger than a maximum diameter of the impeller driving shaft, the collar being detachably mounted on the impeller driving shaft on a rear side of a mounting portion for the driven side coupler, wherein the driven side coupler is operatively engaged and fixed with respect to the impeller driving shaft by an abutment between the collar and the driven side coupler preventing an axial movement responsive to thrust on the impeller driving shaft.
One or more of these and other objects are further accomplished by a coupler mounting structure for a vessel comprising an impeller driving shaft supported on a midsection of a vessel body by a bearing member and driven by an output shaft of an engine; a driven side coupler being mounted on a front end of the impeller driving shaft with a mounting portion; a drive side coupler being operatively engaged with the driven side coupler for transmitting a driving force from the engine output shaft; a collar having a diameter larger than a maximum diameter of the impeller driving shaft, the collar being detachably mounted on the impeller driving shaft on a rear side of the mounting portion for the driven side coupler, wherein the driven side coupler is operatively engaged and fixed with respect to the impeller driving shaft by an abutment between the collar and the driven side coupler preventing an axial movement responsive to thrust on the impeller driving shaft.
In the coupler mounting structure for vessels according to the above, relative movement (and thus relative vibration) between the shaft and the driven side coupler at the mounting portion of the driven side coupler does not occur, and durability is improved at the mounting portion of the driven side coupler. In addition, since the diameter of the collar is larger than the maximum diameter of the shaft, the driven side coupler can be fixedly secured with respect to the shaft by this collar. Since the collar is detachably mounted on the shaft, the shaft can be pulled out rearward of the vessel body by removing the driven side coupler and the collar from the shaft. Accordingly, maintenance of the shaft can be performed easily. If the collar is divided two or more pieces in the circumferential direction, the collar can easily be removed from the shaft.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.